Showing papers on "Polymer blend published in 1990"

Article having non-crosslinked crystallized polymer coatings

Abstract: A non-crosslinked crystallized polymer or polymer blending coating is disclosed for articles that come into contact with bodily fluids. The polymer or polymer blend to be used is crystallizable and is stable in the presence of water at temperatures of up to about 60° C. when in the crystalline state. The polymer or polymer blend is dissolved in a solvent, such as water or dimethyl sulfoxide (DMSO), and is coated on the article. The polymer coating is then crystallized, generally by heat treatment, providing both toughness and increased adherence of the coating to the article without ready dissolution when the article comes into contact with fluids.

Polymer Blends Containing Liquid Crystals: A Review

Abstract: This paper reviews the literature of polymer blends containing low and high molar mass liquid crystals. Low molar mass liquid crystals have been used as plasticizers for thermoplastic polymers and in applications such as electro-optics, optical recording media, and membranes. High molar mass liquid crystalline polymers have been primarily used in polymer blends as processing aids and as an incipient reinforcing phase for “self-reinforced” materials. This review discusses the phase behavior, rheology, and mechanical properties of these blends.

Electrically conductive polymeric materials and use thereof

Abstract: This invention is concerned with an electrically conductive polymer blend composition which is a liquid compatible blend, comprising a doped product formed form blending a first solution comprising a Lewis base electrically conductive polymer in undoped form in a first organic solvent with a second solution comprising a Lewis acid polymer dopant in a second organic solvent, wherein said Lewis acid polymer dopant dopes said Lewis base electrically conductive polymer in undoped form to obtain said electrically conductive polymer blend, the resulting doped conductive product being soluble in the combination of said first and said second organic solvents and mixable at the molecular level.

Interference microscopy on thin diblock copolymer films

Abstract: Etude de l'orientation des microdomaines lamellaires et de la quantification de l'epaisseur du film qui en resulte pour des films de copolymere styrene/methacrylate de methyle prepares par coulee de solution du polymere sur un substrat de silicium puis recuits au dessus de Tg

The morphology of extruded blends containing a thermotropic liquid crystalline polymer

Abstract: Three different polymer blends consisting of an isotropic matrix and a ther-motropic liquid crystalline polymer (LCP) as the reinforcement were extruded. Polycarbonate (PC) and polyetherimide (PEI) were the two matrices, and the LCPs used were Vectraw A950 of Hoechst-Celanese, a copolyester of hydroxybenzoic and 2,6 hydroxynaphthoic acids and an LCP of Granmont Inc., a condensation polymer of terephthalic acid, (l-phenylethyl)hydroquinone, and phenylhydroqui-none. These extrudates were characterized by a quantitative morphological technique to determine the percentage of LCP present as fibrils and the average domain diameter. These experimental observations were then coupled with the component Theological behavior and a simple heat transfer analysis to explain the morphology and property differences between the blends. Blends with the Granmont LCP showed no appreciable increase In the quantity of fibrils with draw ratio, for example, whereas the amount of fibrils in Vectra® blends tended to increase to a plateau with draw. The tensile modulus of the blends agreed well with composite theory, with average fibril moduli of 24.6 GPa and 23,3 GPa for Vectra® and the Granmont LCP, respectively. These differences can be explained in terms of the cooling behavior of the LCPs.

In situ reactive compatibilization in polymer blends : effects of functional group concentrations

Abstract: Polystyrene (PS) and polyethylene (PE), along with their reactive counterparts, i.e., polystyrene having oxazoline reactive groups (OPS) and polyethylene with carboxylic acid groups (CPE), were melt blended in a Rheomix mixer. These blends were prepared by mixing these polymers in various proportions under a variety of conditions. In an alternate procedure the OPS, CPE graft polymer (OPS-g-CPE) was prepared by melt blending these two polymers beforehand, and subsequently this grafted polymer was used as a compatibilizer for PS–PE blends. The effects of the addition of OPS and CPE, on the one hand, and OPS-g-CPE, on the other hand, on the compatibility of PS–PE blends were investigated. The morphology of these blends was examined with a scanning electron microscope (SEM) and related to their tensile properties. The PS–PE blends are found to have the typical coarse morphology of incompatible blends and poor tensile properties while their reactive counterparts, OPS-CPE blends, have fine grain microstructure and show improved tensile strength throughout the range and improved elongation in the PE-rich blends. Relatively low concentrations of the reactive pair, oxazoline and carboxylic acid, are shown to be necessary to produce improved compatibility. The preblended graft copolymer OPS-g-CPE imparts compatibility to PS–PE blends also but not as effectively. This suggests that the addition of OPS and CPE during melt mixing of PS and PE forms OPS-g-CPE polymer at the interface and that these ingredients act as “in situ reactive compatibilizers” which improve physical properties.

Synthesis of amino acid-derived bioerodible polymers

Abstract: Novel amino acid-derived polycarbonates and amino acid-derived diphenol compound starting materials from which the polycarbonates are polymerized. Polymer blends of the amino acid-derived polycarbonates with polyiminocarbonates prepared from identical amino acid-derived diphenol starting materials.

Mechanical behavior related to the phase morphology of PC/SAN polymer blends

Abstract: The phase morphology of intensively melt mixed and injection moulded bisphenol-A polycarbonate (PC)/styrene-acrylonitrile copolymer (SAN) blends changes on annealing above the glass-transition temperature (Tg) of both components. For the selected PC and SAN resins, the phase morphology of the 60/40 PC/SAN blend changes from a fine dispersion of the PC phase in a SAN matrix to a coarse co-continuous phase network, whereas a co-continuous 70/30 PC/SAN blend changes to a dispersion of SAN domains in a PC matrix. The effect of the blend morphology on dynamic mechanical properties and ambient tensile stress-strain properties have been studied thoroughly. An increase of the storage modulus between Tg(SAN) and Tg(PC) is observed with increasing coarsening of the phase structure until a continuous PC matrix is formed. The coarsening of the phase structure of the blends gives rise to a transition from ductile to brittle fracture. The loss in ductility is related to a decrease in relative amount of interface and a transition in the type of dispersion.

Liquid-crystalline polymers

Abstract: Current Topics in Liquid-Crystalline Polymers Polyesters of 4,4'-Biphenyidicarboxylic Acid and Aliphatic Glycols for High-Performance Plastics Thermotropic Aromatic Copolyesters Having Ordered Comonomer Sequences: Synthesis and Properties All-Aromatic Liquid-Crystalline Polyterephthalates of Phenylhydroquinone with Diphenylether and Diphenylketone Linkages Thermotropic Main-Chain Polyethers Based on Bis(4-hydroxyphenoxy)-p-xylene Synthesis and Chemical Modification of Chiral, Liquid-Crystalline Poly(ester*b-sulfide)s Liquid-Crystalline Character of Novel Main-Chain Oligophosphates Bearing Lipophilic or Mesogenic Moieties Thermotropic Poly(ester-co-carbonate) Structures and Thermal Properties of Liquid-Crystalline Poly(ester-co-carbonate) Synthesis and Microstructure of Aromatic Copolyesters Synthesis, Characterization, and Photochemistry of a Cinnamate-Containing Liquid-Crystalline Side-Chain Polymer All-Hydrocarbon Liquid Crystalline Polymers Amorphous-Liquid-Crystalline, Side-Chain, AB Block Copolymers: Synthesis and Morphology Side-Chain Liquid-Crystalline Polyphosphazenes Rigid Rod Molecules as Liquid-Crystalline Thermosets Synthesis, Structure, and Properties of Functionalized Liquid-Crystalline Polymers Chemical Heterogeneity in Liquid-Crystalline Polyesters Light Microscopy of Liquid-Crystalline Polymers Solid-State Structures of a Homologous Series of Mesogenic Aromatic-Aliphatic Azomethine Ether Polymers Copolymerlike Structures of Nematic Nitroimine Dimers Simulation and Evaluation of Polymorphism in the Solid State of a Rigid Rod Aramid Calorimetric Investigation of the Glass Transition in Main-Chain Nematic Polymers: Molecular Mass Dependence of the Heat Capacity Increment at the Glass Transition Liquid-Crystalline Polymers: A Unifying Thermodynamics-Based Scheme Solubilities, Processabilities, and Head-to-Tail Polymerization of Liquid-Crystalline Polymers, including First Super-Strong Polymers Molecular Motion in the Homopolyester of 2-Hydroxybenzoic Acid Effect of Shear History on the Rheological Behavior of Lyotropic Liquid Crystals Shrinkage in Parts Molded from Thermotropic Liquid-Crystalline Polymers: Dependence upon Part Geometry and Filler Contents Blending of Polymer Liquid Crystals with Engineering Polymers: The Importance of Phase Diagrams Novel Composites from Blends of Amorphous and Semi-crystalline Engineering Thermoplastics with Liquid-Crystalline Polymers Investigations into the Structure of Liquid-Crystalline Polymer Blends Kinetics of Phase Segregation in Thermotropic Liquid-Crystalline Copolyester and Polyether Imide Blends Polymer-Dispersed Liquid Crystals

Miscibility of polymer blends investigated by 1H spin diffusion and 13C NMR detection

Abstract: The miscibility of two high-performance polymers, an aromatic poly(ether-imide) and a poly(aryl-ether-ketone), was investigated by a novel combination of solid-state NMR techniques. This involves a new type of selection of 1H magnetization based on chemical shift differences, 1H spin diffusion during the mixing time and high-resolution 13C detection. Mixing of components on a molecular scale is proved directly.

Rheological behavior of polydimethylsiloxane/polyoxyethylene blends in the melt. Emulsion model of two viscoelastic liquids

Abstract: The linear viscoelastic behavior of two‐phase polymer blends in the melt is characterized by high values of storage modulus at low frequencies and by long relaxation times. The variation of dynamic moduli with frequency could be explained with an emulsion model as developed by Oldroyd. This model allows us to take in account the viscoelastic behavior of each phase, as well as characteristic parameters of the blends like volume fraction, interfacial tension, and size of inclusions. Experimental results on polydimethylsiloxane/polyoxyethylene‐diol blends are found to be in good accordance with Oldroyd’s emulsion law. The terminal relaxation process of the blend can be assigned to the geometric relaxation of the inclusions.

Processing aid for polymers

Abstract: I. Polymer blend composition having improved processibility and comprising: 1) a difficultly-melt-processible polymer and 0.002 - 0.5 wt. % of one more fluoropolymer process aids wherein the fluoropolymer has a fluorine to carbon ratio of at least 1:2, is capable of forming a die-coating film under the prevailing conditions of extrusion temperature and pressure, and contains an effective amount of polar functional polymer chain end groups, -W, wherein -W is selected from -COF, -SO3M, -OSO3M and -COOM, wherein M is hydrogen, a metal cation, preferably an alkali or alkaline earth metal cation, or a quaternary ammonium cation; or 2) (a) a major portion of a difficultly melt-processible polymer and (b) a minor portion of: (1) at least an effective amount, to improve processibility, of a fluorocarbon copolymer which at the melt-processing temperature of (a) is either in a melted form if crystalline, or is above its glass transition temperature if amorphous, and (2) at least an effective amount, to improve processibility, of at least one tetrafluoroethylene homopolymer or copolymer of tetrafluoroethylene and at least one monomer copolymerizable therewith, wherein the mole ratio of fluorine to hydrogen is at least 1:1, and which is solid at the melt-processing temperature of (a); II. masterbatches comprised of a processing aid; and III. processes utilizing a processing aid.

Poly(Phenylene oxide)/polyamide blends via reactive extrusion

Abstract: Reactive extrusion of functionalized polymers provides a convenient, commercially attractive route for the preparation of copolymers useful in compatibilization of polymer blends. In the current study, the grafting chemistry of maleic anhydride to poly(phenylene oxide) in the absence of a radical initiator is contrasted to that of efficient quinone-methide trapping agents such as maleimides. In the case of maleic anhydride, functionalization is shown to occur randomly along the polymer backbone whereas maleimides react to give both main chain and end-group derivatives. Use of this anhydride-functionalized polyfphenylene oxide and an end-group functionalized analog in blends with polyamide-6,6 affords high levels of graft and diblock copolymers respectively, sufficient for the preparation of highly ductile materials. The properties of these polyamide blends are found to depend on the amount of copolymer formed during extrusion with final copolymer levels being in turn returned to the degree of anhydride functionalization. The properties and morphology of blends containing graft or diblock copolymers derived from main-chain and end-group functionality respectively, are rationalized in terms of the relative effectiveness of different copolymer structures in blend compatibilization.

Impact-resistant polymer blends of olefin polymers, polyamides, and terpolymer compatibilizers

Abstract: Blended polymer compositions are described which comprise (I) from about 1% to about 98% by weight of at least one olefin polymer; (II) from about 1% to about 98% by weight of at least one polyamide; (III) an effective amount of a compatibilizing agent which comprises at least one terpolymer of an alpha-olefin, at least one acrylic ester, and an alpha,beta-olefinically unsaturated dicarboxylic acid reagent, or a glycidyl acrylate; and (IV) from 0 to about 25% by weight of at least one auxiliary compatibilizing agent selected from the group consisting of (IVa) at least one selectively hydrogenated block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene to which has been grafted, an alpha,beta-olefinically unsaturated carboxylic acid reagent; (IVb) at least one polymer which is the product of the reaction of an alpha-olefin polymer and an alpha,beta-olefinically unsaturated carboxylic acid reagent; and (IVc) a mixture of (III) and (IVa) and/or (IVb) reacted in the presence of a radical initiator provided that when the blended polymer contains one or more of the auxiliary compatibilizing agents (IVa) or (IVb), the blended polymer is free of other polymers of vinyl aromatic hydrocarbons.

Die-cuttable and dispensable deformable labels

Abstract: A film facestock useful for making labels for use on deformable substrates, which labels are die-cuttable and dispensable, the film facestock including a layer of a polymer blend which includes an ethylenic material, a styrenic material, and a compatibilizing material.

Impact resistant polymer blends

Abstract: Disclosed is a polymer blend having improved low-temperature impact strength comprising a copolyester of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, and a styrene-butadiene block copolymer.

Miscibility and mechanical properties of polymer blends

Abstract: The tensile properties of 16 blends prepared from 12 different polymers were investigated in the whole composition range. The composition dependence of Young's modulus has shown less, while that of the yield and ultimate properties exhibited more significant variations with miscibility. The quantitative evaluation of the yield stress and tensile strength data resulted in a parameter, which could be related to the interfacial tension and miscibility.

Phase morphology coarsening and quantitative morphological characterization of a 60/40 blend of polycarbonate of bisphenol a (pc) and poly(styrene‐bco‐acrylonitrile) (san)

Abstract: A 60/40 polymer blend of polycarbonate of bisphenol A (PC) with a styrene-co-acrylonitrile (SAN) copolymer was prepared by melt compounding. Injection molded sheets of this, blend were annealed at 200°C as a function of time. The phase morphology of these sheets, studied using transmission and scanning electron microscopy, was found to coarsen as a function of the annealing time. Using the Chalkey procedure, the microstructure of the annealed blends was quantified. Initial tensile stress-strain data highlight the influence of microstructure on ductility for these co-continuous blends.

Filled polymeric blend

Abstract: Filled polymer blends comprising a polycarbonate, a rubber modified copolymer of a vinyl aromatic monomer and from 4 to 18 weight percent of an inorganic filler.

Affinity membranes having pendant hydroxy groups and processes for the preparation and use thereof

Abstract: Polymeric affinity membranes comprise a precursor filtration membrane and a plurality of reaction sites provided on the surface of the membrane selective to binding a specific biological material. A process for the preparation of such affinity membranes includes the steps of providing a copolymer compatible with a water insoluble polymer matrix and having a plurality of hydroxyl groups, activating the hydroxyl groups with a compound selected from the group consisting of organic compounds reactive with a hydroxyl group in the presence of a water miscible solvent to provide a derivatized copolymer containing active adducts, forming a solution of the derivatized copolymer and the polymer matrix to form a polymer blend solution, casting the polymer blend solution and, quenching the cast polymer blend solution in water. A process for selectively removing biological materials from fluids includes the step of passing the fluids over an affinity membrane which comprises a precursor filtration membrane and a plurality of reaction sites provided on the surface of the membrane selective to binding a specific biological material.

Inert electrode comprising a conductive coating polymer blend formed of polyanisidine and polyacrylonitrile

Abstract: The compound ortho-methoxyaniline (o-anisidine) can be polymerized by both chemical and electrochemical means to produce polyanisidine, a soluble polymer of high electrical conductivity Also called poly-o-methoxyaniline or PANIS, polyanisidine can be further blended with various other polymers enabling construction of devices with desirable electrical, optical and physical properties Oxidative polymerization yields have been increased to 47 percent with no apparent loss in electrical conductivity PANIS has been blended with polystyrene, polyacrylonitrile, polyethylene oxide and poly(trimethyl hexamethylene terephthalamide) (nylon) to form free-standing, stable, flexible films and fibers having electrical resistance values dependent upon the concentration of PANIS The applicability of PANIS technology has been demonstrated with the construction of three devices: a switching device that will change color upon the application of positive and negative voltages, an inert polymer electrode, and an electromagnetically shielded connector

Reptation in semidilute solutions of wormlike polymers

Abstract: Finally, some speculations appear worthwhile to be mentioned, namely, some interesting implications of the present findings for the discussion of the processes taking place in the preparation of polymer blends. If two-phase mixtures of polymer A and polymer B are prepared starting from homogeneous systems (e.g. by changing the variables of state or by evaporating a solvent) and equilibrium cannot be reached, molecules of polymer A will be captured in the phase rich in B and vice versa. This means that the concentration profile in the interfacial region of

Flow-induced mixing of blends of poly(ethylene-vinyl acetate) and solution chlorinated polyethylene

Abstract: A rheooptical device was constructed to monitor phase changes in polymer blends undergoing simple shear flow. Light scattering experiments during shear flow of blends of EVA and SCPE indicated that stress improves the miscibility of the two polymers. This is interpreted in terms of a stress-dependent phase diagram in which the phase boundary of a polymer mixture that exhibits a lower critical solution temperature is shifted upward in temperature due to the application of stress

Effect of added block copolymer on phase-separation kinetics of a polymer blend. 1. A light-scattering study

Abstract: L'addition de copolymere bisequence styrene/butadiene a un melange polystyrene/polybutadiene de masse moleculaire faible ralentit la croissance des domaines de separation de phase. Cet effet est attribue a la reduction de la tension interfaciale entre les phases demixees due a l'accumulation du copolymere